Pressure of the unsaturated solution

This is Babo s law, that the ratio of tlir vapour pn ss m H nl solvent and solution does not changv with tin t mp( rniun true only as a limit for increasing dilution. 

As the cycle is at constant t(an )eraturts tlu md, work accomplished must be zero, and wtj have tlu (Mpiaiiou 

In accordance with the order chosen, in which first a pair of substances which practically do not mix was briefly dealt with, then the case of simple solubility, in which only one of the two bodies (the liquid, the solvent) takes up the other (the soluble solid), we come now to the third case, in which each substance takes up the other. This third case is known to be that of many pairs of liquids, e. g. ether and water, so that the consideration of it follows naturally on such observed instances. The composition of the two liquid layers will be taken first, then that of the vapour. 

This may be expressed graphically by the annexed Fig. 14. All possible states, from 100°/ water to 100°/ ether, are shown along ad and ak on ad the proportions taken, on ae the mixtures produced ab then stands for the unsaturated solutions of ether in water, and bisects 

The study of the behaviour of a pair of li iuids thus comes essentially to be the determination at diilenait temperatures of the ratios expressed by bo and 

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